The AC motors (asynchronous and synchronous) ert· attractive option for variable speed drive applications The unified approach to the control system design based on the sliding mode control method is presented in this paper.The design procedure and experimental results show that this approach gives simple structure of the control system and good behavior of the system in transient and steady state operation.

Switching converters are nonlinear dynamic systems of variable structure. The control of output variables is accomplished by the proper choice of sequence and time duration of OFF and ON states of the switches. The theory of VSS (Variable Structure Systems) and deliberate introduction of sliding modes makes possible realization of rather simple and yet quite efficient control schemes for various types of converters (DC-DC, AC-AC, DC-AC). This paper presents a method for control system synthesis of DC-AC converters in the class of VSS systems.

This paper presents the basic results of the research aimed at finding out what are the potential applications of the sliding mode in the control system synthesis of AC and DC motor drives. The general method for design of control systems with "deliberately introduced" sliding mode motion can be divided into two steps: the first - selection of desired character of the control process and selection of functions that describe descrepiancy from the desired process, the second: - selection of the control vector such that the functions that describe descrepiancies are equal to zero. A design approach, based on this method, for the design of control systems of both DC and AC machines is presented in the paper. Similarities between the algorthms are pointed out.

The results of the research concerned with the problem of induction motor control system synthesis using variable structure systems theory is presented. The procedure of control systems synthesis for the control of position speed and torque is given, as well as basic experimental results and problems related to realization of the proposed control algorithms.